using of outbound process code

Hi to all ,

My querry is as follows ,

as we know we send the material master data by using bd10 stand alone program .and we will get the materail master data by using inbound program bd11 , in inbound program we are using inbound processcode DEBM , and we are attatching this process code to inbound function moudle .

but my question is when we will make use of outbound process code . in outbound program we read the data from databse and to populate into data segments of idoc . then